1. Field of the Invention
This invention relates to a method and apparatus for completion of oil, gas and/or hydrothermal wells. More particularly, this invention relates to the application of laser energy for initiating or promoting the flow of a desired resource, e.g. oil, into a wellbore, referred to herein as well completion.
2. Description of Related Art
Once the drilling of a well has been completed, fluid flow into the well is initiated by perforation of the well casing or liner. Such perforations are created using bullets or shaped charges for establishing flow of oil or gas from the geologic formations into the wellbore. The perforations typically extend a few inches into the formation. However, there are numerous problems with this approach. First, the melt from shaped charges or debris from the bullet impact usually reduces the permeability of the producing formations resulting in a substantial reduction in production rate. Second, these techniques involve the transportation and handling of high power explosives and are causes of serious safety and security concerns. Third, the impact of the bullet into the formation also produces fine grains that can plug the pore throat, thereby reducing the production rate.
Additionally, other steps for initiating fluid flow may also be required, depending, at least in part, on the physical properties of the fluid in question and the characteristics of the rock formation surrounding the well. Fluid flow may be inhibited in situations involving highly viscous fluids and/or low permeability formations. Highly viscous fluids do not flow easily. As a result of the decreased rate of flow, efficiency is lowered and overall production rate decreases. The same is true for low permeability formations. In extreme cases, these factors reduce the flow rate to zero, halting production entirely.
One conventional approach to addressing the problem of fluid flow is in situ combustion in which oxygen is injected down hole and burned to induce heating effects. However, the effectiveness of burning oxygen is dependent upon the type of rock in the rock formation. In addition, the technique of burning oxygen affects only the area of initial contact.